A new small-volume chamber made of highly reflecting material has been designed in order to improve the response of FDPM system to optical property changes. Optical properties such as the effective scattering coefficient of malignant cell suspensions (MCF7: human breast carcinoma, SVT2: transformed mouse fibroblast) and subcellular organelles have been measured using FDPM. Experiments demonstrated that optical monitoring of cell physiology could be quantified using our FDPM system, by recording scattering changes due to osmotic and non-osmotic cell responses. Scattering dependence on microstructures is expected to lead to possible tissue differentiation and tumor detection using scattering contrast.